jelaird, I used 1.5" standoffs from RCshowcase to mount the ZDZ80. The capscrews are 10-32 x 2.5" with blindnuts behind the firewall. I had to cut the firewall for carb clearance. Also a picture on Chiefaircraft.com.....link below.
http://www.chiefaircraft.com/Models/...A_ZDZ_APDT.jpg